Pulsator for milking machines



Feb. 20, 1945. E QRSBERG; 2,369,731

PULSATOR FOR MILKINGr MACHINES Filed June 11, 1942 2 Sheets-Sheet 1 mam/r0 rz #zzyugf 521535627 Patented Feb. 20, 1945 UNITED STATE 5- :FIATENT 'OliFl-CE.

7 2,369,731 PULSATOR FOR MILKING MACHINES Application.

In 'iSweden '12 Claims I For efiicientoperation of manypneumatically driven devices, of which milking machines arelan containers,- of a sm'all'aquantity oi suitable fluid completely separated from the surroundings and thus protected from entrance of impurities. One device Iusingthis principle isdescribed in 11.8.; PatentINo. .1,750.634, is'sued to E. A. .Forsberg on March 18,1930. v, f I H The presentinvention employs the sameprinciple .for control but difiers'substantially therefrom inits mechanical construction.

- the accompanying drawings, which illustrate embodiments of ,my invention;

, .Figure 1 is a longitudinal section-showing the construction of "apreferred form of pulsator. Figure 2 is a fpartialsection or an alternative form ofv motor member adapted for use with the same control and valve members shown in Fig. .1.

assignor Sweden,

movement forces air through port T to chamberU or draws air from chamber U; said chamber'being always at atmospheric pressure but closed from the surrounding air and dust by the loose flexible diaphragm V.

Attac'hed to the left endof rod 1, reciprocable in chamber D and separating it from chamber L, is a small piston head 'FLrigidly attached to a larger piston head K reciprocable in chamber L and separating it from chamber M. 'A desirable ratio for the dimension of pistons K andF. is such that the diameter of the former is the square root of two times that of the latter.

-ChamberL is connected, through port A, with vacuum passage A. Chamber M is connected througha port R with 'apassage R. Passage R communicates at one end with. chamber [N and at its other end is adapted for connection with one. pair of teat cups. Passage S communicates at one end with chamber? and at its other end is adapted for connection with another pair of.

teat cups.

Figure 3 is :a .similaipartialsection showing another form. of .motor member.

Thepulsator adapted for operation bythe difference betweentwopneumatic pressures, the higher being atmospheric and the lower, usually abouthalf of atmosphricfhereinafter referred to as vacuum.

gReierrin g to Fig- 1-: A

andthechamber' B at .th center .of adouble v I is alpassageproviding const'antcommunication between thevacuum valve C through which a rod I has alimited longitudinal movement. .The chamber D at the left, and chambers E and, G at the right, of

valve'C are connected by passages D and G with the urrounding atmosphere. The left head of double valve ,initslmovement to left and right in chamber P,contacts alternately with a smaller, valve seat adjacent chamber D and a larger seat adjacen't chamber B,'while the rightv head, in chamber'N, contacts alternately with a Air also flows from and small diaphragms K of the double valve pheric pressure on The construction'shown in Fig. 2 and its operation'are similar to that of Fig.1 except that large and F are substituted for the large and small pistons V The chambers correspon'ding'to chambers M and L of Fig. 1 are lettered M andL". r g

The construction shown in Fig. 3 'difiers from that shown in Fig. 1 in that a 'continuous'force toward the right is obtained by aspring W instead of by providing a vacuum between differentialpistons. The chambers on opposite ends of the piston 1" are marked M and D The operation of the pulsator shown in Fig. 1 will be explained. I

Assuming that the moving element has 'completed its stroke. to the left and the bellows H is full of air at atmospheric pressure: Air can flow through'passageG' and chambers G and 'E' to chamber N whereit' presses the right hand end C toward the left because its other side is "exposed to the vacuum of large diameter chamber B. This force is opposed by atmospheric pressure from chamber D but be cause this chamber is smaller the net 'force' is toward the left. v

chamber N, through paschamber M. With atmossages R and R, to v the left end and vacuum on the right end of large piston K the force toward larger eatjadiacent chamber B and a smaller seat adjacent chamber E.

A bellows H,-,inside chamber G,.is compressed and elongated by movement, of rod I and in its the rightis much greater than that toward the leftifromsmaller piston]. with atmospheric pressure on its right .end and vacuum on its left end. The pistons and the rod I begin to move K and F or Fig. 1. p

toward th right and continue to so move, as fast as they can force air out of bellows H through port T, until the boss or on piston F contacts the left end I) of the double valve C. Here they pause until flow of air out of the bellows H reduces its resistance to movement toward the right below the difference between the force toward the right, from piston K and that toward the left from valve C, wherefor valve C starts toward the right. As soon as the right head of valve C leaves its seat, its resistance to movement toward the right ceases and the stroke of the valve and the rod I with its attached pistons and bellows toward the right is quickly completed.

Chamber M is now connected, through passages R and R, chambers N and B and passage A with vacuum. Because there is vacuum on both sides of piston K it has no force in either direction, but piston F, with atmospheric pressure at its right end and vacuum at its left, has a strong force toward the left and, through rod I, expands bellows H, as fast as air can flow in through port '1, until the boss adjacent the bellows contacts the right end of double valve 0. It will then pause, as it did in the movement toward the right, until the resistance of the bellows becomes less than the difference between the leftward force of piston F and resistance to movement of valve C, which is now a force toward the right, when the valve and other parts will quickly complete'their stroke and conditions will be those at the start.

The operation of the motor members shown in Fig. 2 is the same as that of those shown in Fig. 1.

In the motor shown in Fig. 3, with parts in the position shown, there is atmospheric pressure against both ends of piston F and thespring W will move it toward the right as fast as it can force air out of the bellows until, as explained for Fig. 1, valve C reverses and chamber M is connected with vacuum. Now atmospheric pressure in chamber D will move piston toward the left until, as explained for Fig. 1, valve C returns to the position shown and the operation is repeated.

I claim:

1. A pneumatic pulsator comprising means providing a channel adapted for connection with a source of relatively low pneumatic pressure and a passage in which pneumatic pulsations are adapted to be produced, a member comprising valves adapted in one position to connect said passage with said channel and in the other position to connect said passage with a source of relative- 1y high pneumatic pressure, an expansible and contractible fluid-containing chamber, a'second fluid-containing chamber, means allowing only restricted fiow of fluid between said chambers, each of said chambers being otherwise closed against admission or escape of air, a valve-actuator movable independently of said valves in one direction to first contract the first named chamber to cause fluid to flow therefrom into the other chamber and to then shift said valves from one position to the other and movable in the other direction independently of said valves to first expand the previously contracted chamber to thereby cause fluid to flow into it from the other chamber and to then reverse said valves, said valve actuator having pressure faces one of which is in fluid communication with said passage and which is therefore subjected to alternate high and low pressure by the movement of the valves into their opposite positions, the last named pressure face being of such area that, without changes of preslow pressure sides of the valves contact being of greater diameter than those against which the high pressure sides of the valve contact, whereby the valves, when at either end of their stroke, are held at that end solely by fluid forces and offer resistance to movement by the actuator.

2. A pneumatic pulsator comprising means providing a channel adapted for connection with a source of relatively low pressure and two passages in which pneumatic pulsations are to be produced, a reciprocable member comprising valves adapted in one position to connect one of said passages with said channel and the other with a source of relatively high pressure and in the other position to reverse said connections, an expansible and contractible fluid-containing chamber, a second fluid-containing chamber, means allowing only restricted flow of fluid between said chambers, each of said chambers being otherwise closed against admission or escape of air, a valve-actuator movable independently of said valves in one direction to first contract the first named chamber to cause fluid to flow therefrom to the other chamber and to then shift said valves from one position to the other and movable in the other direction independently of said valves to first expand the previously contracted chamber to thereby cause fluid to flow into it from the other chamber and to then reverse said valves, said valveactuator having pneumatic pressure faces one of which is connected with one of said two passages and which is therefore subjected alternately to high and low pneumatic pressures by the movement of the valves into their opposite positions, the last named pressure face being of such area that, without changes of pressure on other working surfaces, the valve actuator moves in one direction or the other dependent upon whether the last named pressure face is subjected to high or low pneumatic pressure, each of said valves having its opposing faces open to high and low pressure respectively, opposing valve seats for each valve, the seats against which the low pressure sides of the valves contact being of greater diameter than those against which the high pressure sides of the valve contact, whereby the valves, when at either end of their stroke, are held at that end solely by fluid forces and offer resistance to movement by the actuator.

3. A pneumatic pulsator as defined in claim 1 in which said fluid-containing chambers are bounded by three walls, namely, a rigid wall between and common to said chambers, a bellows forming the other wall of one chamber and a flexible wall forming the other wall of the other chamber.

4. A pneumatic pulsator as defined in claim 1 in which said valve-actuator comprises a piston having the specified pressureface that is sub. jected to alternate high and low pressures and having also an opposing pressure face of relative- 1y small area communicating constantly with a source of relatively high pressure, a piston rod extending and slidable throughsaid valve memher, and means movable with the piston and piston rod adapted to contact with the valve member to effect its shift as specified.

5. A pneumatic pulsator as defined in claim 1 vent movement of the piston in the oppositedi? rec'tion'when thefirst named face of the piston is ubjected fto relatively low "pressure, BJ A pneumatic pulsator as define'd'in'claiml "in having -the-specifie'd pressure face that'is-subiic'ted "to alternate high and low pressures and having also an opposingpressure face of relatively "small area communicating constantly with a source or relatively high pressure, the ratio "between-the diameters of the two opposing pr'essure tapes being approximately lzx/Z'. v 'l. -"A' pneumatic pulsator comprising means'pr oadding a channel adapted for connection with a 'seu'rceof relatively low pneumatic pressure and a passage I in which pneumatic pulsations are adapted to be produced, amember comprising valves adapted in one position to connect said passage with said channel and in the other position to connect said passage with a source of relatively high pneumatic. pressure, an expansible and contractible fluid-containing chamber, a second fluid-containing chamber, means allowing only restricted flow of fluid between said chambers, each of said chambers being otherwise closed against admission or escape of air, a valve-actuator comprising two spaced apart diaphragms of different areas and a piston rod connected with both diaphragms, said valve actuator being movable independently of said valves in one direction to contract the first named chamber to cause fluid to flow therefrom into the other chamber and to then shift the valves from one position to the other and movable in the other direction independently of said. valves to first expand the previously contracted chamber to thereby cause fluid to flow into it from the other'chamber and to then reverse the valves, means to maintain the space between the two diaphragms of the valve actuator in connection with a source of low pressure, means adapted to maintain the outer face of the smaller diaphragm subject to a source of higher pressure, and means controlled by said valves in their specified movements to subject the outer face of the larger diaphragm to alternate higher and lower pressures, each of said valves having its opposing faces open to high and low pressure respectively, opposing valve seats for each valve, the seats against which the low pres-v sure sides of the valves contact being of greater diameter than those against which the high pres- .sure sides of the valve contact, whereby the' valves, when at either end of their stroke, are held at that end solely by fluid forces and oiTer resistance to movementby the actuator.

8. A milking machine pulsator comprising a casing, a pneumatic braking device at one end of the casing, a valveactuator comprising a pneumatically controlled device at the other end of the casing and a rod connecting said devices, a double poppet valve, sleeved on said rod, between said devices and having a limited movement in opposite directions, the casing having two ports adapted for constant connection with a source of high pressure, one port between the valve and which said valve actuator comprisesapiston I twormembersofthedoublevalve and having also a-passageadapted in the oppositepositions of the valveto' be -connected alternatelywith one of said high pressure ports and said low pressure port,

thereby producingpneumatic 'pulsations in said passage'means including'a branch from said pas- "actuator whereby said pneumaticipulsations effect movement of the valve actuator infopposite directions, therange of movethan that-of the valve that in the forepart of each of its'movements ysaid rod slides within the valve until the vaIveactuZktQr engages the valve and thereafter shifts the valve from one end positiontd-theother. i 9, A milking machine pulsator comprising a casing, a'pneumatic braking device at oneendof,

the casing, a valve actuator comprising a pneu matically controlled device at the other 'endof the casing-and arodsecuredto and connecting said pneumatically --controlled device and braking l device, two spac'ed' apar't poppet valves and a hub carrying said valves and sleeved "on said rod, thereby providing a double valve, inner and outer valve seats for each valve, the inner valve seats being of a substantially greater radius than the outer valveseats, there being high pressure ports in constant communication with the spaces outside the valves and a low pressure port in constant communication with the space between the valves whereby the opposing pneumatic pressures on the valves tend to hold them in either end position to which they are moved, there being also a pulsation passage between the two valve seats of one of the valves, and means including a branch from said passage to said valve actuator whereby the alternate high and low pressures in said pulsation passage, produced by reciprocation of the valves, effect movement of the valve actuator in opposite directions, the range of the movement of the valve actuator being so much greater than that of the valves that in the forepart of each movement of the valve actuator said rod slides within the valves until the valve actuator engages the valve and, after overcoming the pneumatic force tending to hold the valve from movement, shifts the valve to its opposite position.

10. A milking machine pulsator comprising an enclosing casing, a double poppet valve and a valve actuator, comprising a pneumatically controlled device and a rod, arranged and movable along a common axis; a valve-speed regulator comprising two air-containing chambers bounded by three walls, namely, a rigid wall between and common to said chambers and two walls one at least of which is flexible, there being fluid communication between said chambers of restricted and constant fluid flow capacity, said chambers being otherwise closed against admission or escape of air; said casing having a high pressure port, a low pressure port, and a pulsation pas- ;Jsage; said valve having a limited movement along said axis into two opposite positions, in one of which it connects said pulsation passage with one of said ports and in the other of which it connects said pulsation passage with the other of said ports, means including a branch from said passage to said valve actuator whereby the alternate high and low pressures in said pulsation passage effect movement of the valve actuator alon said axis in respectively opposite directions,

"t o'f th-valve actuator'being so much greater said rod being secured at one end to a flexible wall of the valve spee'd regulator, the valve being sleeved on said rod, the valve actuator, in its said movements, alternately expanding and contracting one of said chambers and in the forepart of each of said movements moving independently of said valve and for the remainder of its movement engaging the valve and shifting it from one to the other of its said positions.

11. A milking machine pulsator comprising a casing having therein ports adapted to communicate with sources of respectively high and low pneumatic pressure and a pulsation conduit, and enclosed within the casing at one end a pneumatic braking device and a valve actuator comprising a pneumatically controlled device at the other end of the casing and a piston rod connecting said two devices; a double poppet valve sleeved on said rod between the valve actuator and the braking device and movable into two opposite positions adapted to connect said ports respectively with said pulsation passage to produce therein alternate high and low pressures, means whereby the alternate high'and low pressures in said pulsation conduit effect movement in opposite directions of the valve actuator and rod along the latters axis against the action of said pneumatic braking device; said braking device comprising two air-containing chambers bounded by three walls, namely, a rigid wall between and common to said chambers, another wall constituting the second wall of one of said chambers and a bellows constituting the second wall of the other of said chambers, there being fluid communication between the two chambers of restricted and constant fluid flow capacity, said chambers being otherwise closed against admission or escape of air; the range of movement of the valve actuator being so much greater than that of the valve that in the forepart of each movement of the valve actuator the rod slides within the valve until the valve actuator engages the valve, after which continued movement of the valve actuator mechanically shifts the valve from one to the other of its opposite positions.

- 12. A milking machine pulsator as defined in 20 claim 8 comprising means adapted to apply to the valve, when seated at either end stroke, differential pneumatic pressures tendin to hold it seated and adapted, when unseated by the valve actuator, to equalize said pneumatic pressures and thereby allow the stroke of the valve to be quickly completed.

ERIK AUGUST FORSBERG. 

